Surface waves
Also called: L-waves, Long waves · Topic: Interior of the Earth: Earthquakes, Volcanoes and the Layered Earth · NCERT: Class 11, Ch 3 "Interior of the Earth"
Meaning
Surface waves form when body waves reach the rocks at the surface. They travel along the surface, not through the inside of the earth. They are the last to arrive on a seismograph, but they do the most damage. They shift rocks and bring buildings down. They vibrate at right angles to their direction of travel. There are two kinds. Love waves shake the ground from side to side. Rayleigh waves roll the ground like ocean waves.
Example
In the Bhuj earthquake of 26 January 2001 (Mw 7.7) in Gujarat, much of the building collapse came from the strong ground shaking that surface waves cause.
Don't confuse with
- Body waves (P and S): these travel through the earth's interior and arrive before surface waves. They are the waves that reveal the inner layers.